<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Iframe Container</title>
</head>
<body>
<div>
    <iframe
            src="iframe_inner.html"
            id="iframe"
    ></iframe>
    <button id="root_button">Button</button>
</div>


</body>
</html>